const STORAGE_KEY='mall'
export default{
    setItem(key,value,module_name){
        if(module_name){
            let val = this.getItem(module_name);
            val[key] =value;
            this.setItem(module_name,val)
        }else{
            let val =this.getStorage();
            val[key] = value;
            window.sessionStorage.setItem(STORAGE_KEY,JSON.stringify(val));
        }


    },
    // 获取某个模块下的属性
    getItem(key,module_name){
        if(module_name){
            let val = this.getItem(module_name);
            if(val) return val[key];
        }
        return this.getStorage()[key];
    },
    getStorage(){
       return JSON.parse(window.sessionStorage.getItem(STORAGE_KEY||'{}'));
    },
    clear(key,module_name){
        let val = this.getStorage();
        if(module_name){
            if(!val[module_name])return;
            delete val[module_name][key];
        }else{
            delete val[key];
        }
        this.setItem(val);
    }
}